Fluid fitting

ABSTRACT

A fluid fitting includes a nut, a sleeve, and a union. The union and the nut may include corresponding stops. Corresponding stops may engage with each other when the nut is sufficiently connected with the union. A method of designing a fluid fitting including a union may include determining a gauge diameter of the union, determining a plane perpendicular to an axis of rotation of the union that includes a center point of the gauge diameter, determining a point of intersection of threads of the union with the perpendicular plane, and/or determining a position of a stop according to an angle from the point of intersection.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication Ser. No. 62/541,903, filed on Aug. 7, 2017, U.S. ProvisionalPatent Application Ser. No. 62/647,640, filed on Mar. 24, 2018, and U.S.Provisional Patent Application Ser. No. 62/662,945, filed on Apr. 26,2018, the disclosures of which are hereby incorporated herein byreference in their entireties.

TECHNICAL FIELD

The present disclosure generally relates to fittings, such as fluidfittings.

BACKGROUND

This background description is set forth below for the purpose ofproviding context only. Therefore, any aspect of this backgrounddescription, to the extent that it does not otherwise qualify as priorart, is neither expressly nor impliedly admitted as prior art againstthe instant disclosure.

With some fluid fittings, such as flareless fittings, it may bedifficult to quickly determine if a sufficient connection has been madebetween a union, a nut, and/or a sleeve. For example, relative axialtravel of a male and female flareless fitting between a minimum torqueand a maximum torque may be about 0.0015 inches, and it may be difficultto ensure that a sufficient connection has been made, such as due totolerance stack up. Using a torque wrench may involve an extendedprocess.

There is a desire for solutions/options that minimize or eliminate oneor more challenges or shortcomings of fluid fittings. The foregoingdiscussion is intended only to illustrate examples of the present fieldand should not be taken as a disavowal of scope.

SUMMARY

In embodiments, a fluid fitting may include a nut, a sleeve, and/or aunion. The union and the nut may include corresponding stops.Corresponding stops may engage with each other when the nut issufficiently connected with the union. Corresponding mating surfaces ofthe sleeve and the union may include a mating angle of less than 12degrees. In embodiments, a mating angle may be about 4 degrees to about6 degrees, and for some embodiments a mating angle may be about 5degrees. Corresponding stops may be helical and/or provide correspondingcircumferential faces. Corresponding stops may include correspondingfingers. Corresponding stops may include at least two stops of the nutand at least two stops of the union. A union and a nut may includecorresponding visual indicators. Corresponding visual indicators mayinclude a first visual indicator of the union and a second visualindicator of the nut. One of the first visual indicator and the secondvisual indicator may include a greater circumferential extent than theother. In embodiments, a union may include a sliding stop of thecorresponding stops. A sliding stop may be connected with the union viaa press fit or interference fit.

With embodiments, a method of designing a fluid fitting may includedetermining a gauge diameter of a union, determining a planeperpendicular to an axis of rotation of the union that includes a centerpoint of the gauge diameter, determining a point of intersection ofthreads of the union with the perpendicular plane, and/or determining aposition of a stop according to an angle from the point of intersection.An angle may correspond to an expected deformation. An expected (oranticipated) deformation may include an expected plastic deformationand/or an expected elastic deformation. A fluid fitting may be formedaccording to the method.

The foregoing and other aspects, features, details, utilities, and/oradvantages of embodiments of the present disclosure will be apparentfrom reading the following description, and from reviewing theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an exploded perspective view generally illustrating anembodiment of a fluid fitting according to teachings of the presentdisclosure.

FIG. 1B is an exploded perspective view generally illustrating anembodiment of a fluid fitting according to teachings of the presentdisclosure.

FIG. 2 is a perspective view generally illustrating an embodiment of afluid fitting according to teachings of the present disclosure.

FIGS. 3A and 3B are perspective views generally illustrating portions ofembodiments of fluid fittings according to teachings of the presentdisclosure.

FIG. 4 is a side view generally illustrating an embodiment of a fluidfitting according to teachings of the present disclosure.

FIG. 5 is a side view generally illustrating an embodiment of a fluidfitting according to teachings of the present disclosure.

FIG. 6 is a side view generally illustrating an embodiment of a fluidfitting according to teachings of the present disclosure.

FIG. 7 is a perspective view generally illustrating embodiments of afluid fitting and an electronic scanner according to teachings of thepresent disclosure.

FIG. 8 is a perspective view generally illustrating embodiments of afluid fitting and an electronic scanner according to teachings of thepresent disclosure.

FIGS. 8A and 8B are perspective views generally illustrating embodimentsof fluid fittings and electronic scanners according to teachings of thepresent disclosure.

FIG. 9 is a perspective view generally illustrating portions of anembodiment of a fluid fitting according to teachings of the presentdisclosure.

FIG. 10 is a perspective view generally illustrating portions of anembodiment of a fluid fitting according to teachings of the presentdisclosure.

FIGS. 11A and 11B are flow diagrams generally illustrating embodimentsof methods of operating a fluid fitting according to teachings of thepresent disclosure.

FIG. 12A is a perspective view generally illustrating an embodiment of afluid fitting according to teachings of the present disclosure.

FIG. 12B is a flow diagram generally illustrating an embodiment of amethod of designing a fluid fitting according to teachings of thepresent disclosure.

FIG. 13 is a cross-sectional view generally illustrating portions of anembodiment of a sleeve according to teachings of the present disclosure.

FIG. 14 is a graphical representation of sealing pressure relative todegrees from a finger-tight position.

FIG. 15 is a perspective view generally illustrating an embodiment of aunion according to teachings of the present disclosure.

FIG. 16 is a flow diagram generally illustrating an embodiment of amethod of designing, manufacturing, and/or verifying a fitting accordingto teachings of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to embodiments of the presentdisclosure, examples of which are described herein and illustrated inthe accompanying drawings. While the present disclosure will bedescribed in conjunction with embodiments and/or examples, it will beunderstood that they are not intended to limit the present disclosure tothese embodiments and/or examples. On the contrary, the presentdisclosure is intended to cover alternatives, modifications andequivalents.

In embodiments, such as generally illustrated in FIGS. 1A, 1B, and 2, afluid fitting 20 may include a sleeve 30, a nut 40, and/or a union 60. Afluid fitting 20 may be configured for connection with a fluid conduit32, 32′ such as a tube or a hose (see, e.g., FIG. 1B). For example andwithout limitation, a sleeve 30 may be connected with (e.g., insertedinto) a fluid conduit 32 and/or a sleeve 30′ may be connected with afluid conduit 32′. A sleeve 30, 30′ may include a flange 34, 34′. Afluid fitting 20 may include an axis 20A about which a nut 40 and/or aunion 60 may rotate.

In embodiments, a nut 40 may be connected with a sleeve 30. For exampleand without limitation, a nut 40 may include an inner surface or flange42 that may engage a flange 34 of a sleeve 30 such that axial movementof the nut 40 in at least one direction (e.g., toward the union 60) maycause axial movement of the sleeve 30. An inner surface or flange 42 maybe disposed at or about a rear end 44 of the nut 40. A nut 40 may engagea sleeve 30 such that the nut 40 may rotate relative to the sleeve 30and/or such that the sleeve 30 may be restricted from moving axiallyrelative to the nut 40 in at least one direction (e.g., away from theunion 60). A nut 40 may include one or more flat portions 46 (or otherformations) that may, for example, be configured for engagement with awrench and/or a hand of a user to cause rotation of the nut 40. A nut 40may include inner threads 48 that may be disposed at or about a frontend 50 of the nut 40.

With embodiments, a union 60 may include a first connection portion 62that may be configured to at least partially receive a portion of asleeve 30. Additionally or alternatively, a first connection portion 62may be configured for connection with a nut 40. For example and withoutlimitation, first connection portion 62 may include an aperture orrecess 64 for at least partially receiving sleeve 30, and/or may includeouter threads 66 that may be configured to engage inner threads 48 ofthe nut 40. A union 60 may include a second connection portion 68 thatmay be configured in the same or a similar manner as the firstconnection portion 62. For example and without limitation, as generallyillustrated in FIG. 1B, the second connection portion 68 may beconfigured for connection with a second sleeve 30′, a second fluidconduit 32′ (e.g., via second sleeve 30′), and/or a second nut 40′.

With embodiments, a union 60 may include a shoulder 70 that may bedisposed (e.g., axially) between the first connection portion 62 and thesecond connection portion 68. The shoulder 70 may include one or moreflat portions 72 (or other formations) that may, for example, beconfigured for engagement with a wrench and/or a hand of a user. Ashoulder 70 may include a greater outer diameter than the firstconnection portion 62 and/or the second connection portion 68.

In embodiments, a nut 40 may be connected to and/or disposed at leastpartially around a sleeve 30, and may then be connected to (e.g.,screwed onto) a union 60. As a nut 40 connects with a union 60, the nut40 may cause the sleeve 30 to move at least partially into an aperture64 of the first connection portion 62 of the union 60, which mayfacilitate fluid communication between the sleeve 30, the fluid conduit32, and/or the union 60.

With embodiments, such as generally illustrated in FIGS. 2, 3A, and 3B,a nut 40 and/or a union 60 may include one or more stops (e.g., stops80, 84) that may limit relative rotation between the nut 40 and theunion 60 (e.g., limit a degree to which the nut 40 may be screwed ontothe union 60) and/or may provide a visual indication of a sufficientconnection between the nut 40 and the union 60. For example and withoutlimitation, a nut 40 may include a first stop 80 and a union 60 mayinclude a second stop 84. The first stop 80 may include a helicalconfiguration and/or may include a first circumferential face 82. Thesecond stop 84 may include a helical configuration that may correspondto the helical configuration of the first stop 80, and/or the secondstop 84 may include a second circumferential face 86 that may correspondto the first circumferential face 82. For example and withoutlimitation, the nut 40 may be screwed onto the union 60 until the firstcircumferential face 82 contacts or engages the second circumferentialface 86. If the first circumferential face 82 is in contact with thesecond circumferential face 86, such contact may provide a tactileand/or visual indication, such as to a viewer/user/inspector, that asufficient connection has been established.

In embodiments, such as generally illustrated in FIG. 4, a first stop 80and a second stop 84 may include corresponding finger configurations.For example and without configuration, a first stop 80 may extend in anaxial direction toward the union 60, and a second stop 84 may extend inan axial direction toward nut 40. The first stop 80 (e.g., a firstfinger) may provide the first circumferential face 82, and the secondstop 84 (e.g., a second finger) may provide the second circumferentialface 86. Rotation of the nut 40 onto the union 60 may continue until thefirst stop 80 contacts or engages the second stop 84. A first stop 80may be fixed to the nut 40, and/or a second stop 84 may be fixed to theunion 60 such that an amount of torque that can be applied to the nut 40and the union 60 while the first stop 80 and the second stop 84 are incontact or engagement may be limited (e.g., first stop 80 and secondstop 84 may restrict and/or prevent further or over-torqueing).

In embodiments, such as generally illustrated in FIG. 5, a first stop 80may be configured to rotate relative to the nut 40, and/or a second stop84 may be configured to rotate relative to the union 60 (e.g., one orboth of the first and second stops 80, 84 may comprise a sliding stop).For example and without limitation, a second stop 84 may be provided bya stop ring 88 that may be press fit or interference fit onto the union60. A stop ring 88 may be connected to the union 60 such that a minimumforce or torque to cause rotation of stop ring 88 may be greater than auser is expected to provide without benefit of a mechanical advantage,such as via a wrench or other tool. If the nut 40 and the union 60continue to be screwed together, after an initial engagement of thefirst stop 80 and the second stop 84 at a design position AP₁, withgreater than the minimum force or torque (e.g., are over-torqued), thefirst stop 80 may cause rotation of the second stop 84 and the stop ring88 from an initial angular position AP₁ to an over-torqued angularposition AP₂. For future or subsequent connections of the nut 40 and theunion 60, the nut 40 may be screwed onto the union 60 until the firststop 80 engages the second stop 84 (e.g., at the over-torqued positionAP₂). Such a configuration may help ensure that with each connection ofa fluid fitting 20, the nut 40 has been screwed onto the union 60 atleast as far as the last connection and/or such that a minimum ordesired axial force has been provided to the sleeve 30, the nut 40,and/or the union 60.

In embodiments, such as generally illustrated in FIG. 6, a nut 40 and/ora union 60 may include a plurality of stops, such as stops 80 ₁, 80 ₂ ofthe nut 40 and stops 84 ₁, 84 ₂ of the union 60. With embodiments, if asufficient connection between a nut 40 and a union 60 is obtained, allof stops 80 ₁, 80 ₂ of nut 40 may be engaged with and/or in contact withall respective stops 84 ₁, 84 ₂ of union 60.

With embodiments, a connection or engagement between stops, such asbetween a first stop 80 and a second stop 84, may provide a first visualindicator that a fluid fitting 20 is sufficiently connected. Inembodiments, such as generally illustrated in FIGS. 7 and 8, a fitting20 may include one or more additional (or alternative) visual indicatorsthat a fitting 20 is sufficiently connected. For example and withoutlimitation, a nut 40 may include a first marking 90, and a union 60 mayinclude a second marking 92 that may align (e.g., circumferentially)with each other if the nut 40 and the union 60 are sufficientlyconnected (e.g., are disposed in a connected configuration). Inembodiments, one of the first marking 90 and the second marking 92 mayinclude a greater circumferential extent than the other (e.g., firstmarking 90 may be configured as a line, second marking 92 may beconfigured as a second line, and the second line may be wider than thefirst line in a circumferential direction). A difference incircumferential extent between the first marking 90 and the secondmarking 92 may, for example, correspond to an expected or anticipatedamount of deformation of the first stop 80 and/or the second stop the 84upon a sufficient connection. A leading edge 94 of the larger marking(e.g., the second marking 92) may correspond to a designposition/alignment for a sufficient connection. Due to deformation, forexample, the nut 40 and the union 60 may be rotated relative to eachother beyond a design position. In such circumstances, the smallermarking (e.g., first marking 80) may not align with leading edge 94 ofthe larger marking, but may still be aligned with at least some portionof the larger marking, which may provide a visual indication that theconnection is sufficient.

With embodiments, a range of expected deformation may be determinedaccording to appropriate maximum and/or minimum limits. Minimum limitsmay be determined according to an expected loss of pressure during anexpected life of the fitting 20. An expect loss of pressure may, forexample and without limitation, be a factor of repeated use, vibration,component tolerances, and/or temperature variation, among others.Maximum limits may be determined according to one or more of a maximum(or “excessive”) torque and/or a torque at which galling occurs.

In embodiments, such as generally illustrated in FIG. 8, a first marking90 and a second marking 92, when aligned, may provide a particulardesign, which may include or take the form of a word. For example andwithout limitation, first marking 90 may include a first portion of aword (e.g., a bottom half of the word “VISUAL”) and second marking 92may include a second portion of a word (e.g., a top half of the word“VISUAL”). An optical device 96 may be configured to read the word(e.g., via optical character recognition or OCR) to determine if asuccessful connection has been made.

With embodiments, such as generally illustrated in FIGS. 8A, and 8B, afluid fitting 20 may include markings (e.g., markings 90′, 92′, 90″,92″) that may be configured to form a barcode or marking that may bereadable via an optical device 96 (e.g., may be machine readable). Forexample and without limitation, markings 90′, 92′ may form aone-dimensional barcode upon a successful connection (see, e.g., FIG.8A). One of markings 90′, 92′ may be longer than the other. As generallyillustrated in FIG. 8B, a fluid fitting 20 may include markings 90″, 92″that may form a two-dimensional barcode (e.g., a QR code) upon asuccessful connection.

In embodiments, such as generally illustrated in FIGS. 9 and 10, asleeve 30 may include an outer mating surface 100 that may correspond toand/or engage an inner mating surface 104 of a union 60. The outermating surface 100 may include an outer mating angle 102 (which may beprovided relative to an axial direction). The inner mating surface 104may include an inner mating angle 106 (which also may be providedrelative to an axial direction). The outer mating angle 102 and theinner mating angle 106 may be about or substantially the same. In somedesign configurations, the outer mating angle 102 and/or the innermating angle 106 may be about 12 degrees, such as, for example, about 10degrees to about 14 degrees, about 11 degrees to about 13 degrees, orabout 11.5 degrees to about 12.5 degrees. With embodiments, the outermating angle 102 and/or the inner mating angle 106 may be greater orless than 12 degrees. For example and without limitation, the outermating angle 102 and/or the inner mating angle 106 may be about 4degrees to about 10 degrees, about 5 degrees to about 8 degrees, about 4degrees to about 6 degrees, and/or about 5 degrees. Smaller matingangles may facilitate increased axial travel of the nut 40 and the union60 between a minimum torque of a fluid fitting 20 and a maximum torqueof a fluid fitting 20, which may, for example, accommodate for a greaterrange of manufacturing tolerances.

With reference to FIG. 11A, a method 110 of using/operating a fluidfitting 20 for some embodiments may include connecting a sleeve 30 witha fluid conduit 32 and/or connecting a sleeve 30 with a nut 40 (step112). The nut 40 may be connected with (e.g., screwed onto) a union 60,which may connect and/or cause engagement between the sleeve 30 and theunion 60 (step 114). The nut 40 and/or union 60 may be screwed together(step 116) until a first stop 80 (e.g., of the nut 40) engages/contactsa second stop 84 (e.g., of the union 60) (step 118). The first stop 80and the second stop 84 may restrict and/or prevent further relativerotation of the nut 40 and the union 60 in a tightening direction (e.g.,may restrict/prevent over-tightening/over-torqueing) (step 120). Contactbetween the first stop 80 and the second stop 84 may provide a visualindication of a sufficient connection between the nut 40 and the union60 that may be verified (e.g., visually), such as by a user/inspectorand/or without using a torque wrench or some other torquemeasuring/indicating device (step 122).

Additionally or alternatively, with embodiments, verifying a sufficientconnection (step 122) may include scanning a fluid fitting 20 with anoptical device 96 (see, e.g., FIGS. 8, 8A, and 8B). An optical device orscanner 96 (e.g., an electronic optical device or scanner) may includeone or more of a variety of devices that may be configured to scan afitting 20 to determine whether a sufficient connection has been made.For example and without limitation, an optical device 96 may include acamera, a scanner, a handheld scanner, a mobile scanner, a smartphone, abarcode reader, and/or other devices. Examples of optical devices 96 aresold by Cognex Corporation. In embodiments, an optical device 96 may beconfigured to scan a first stop 80 and a second stop 84 to determine ifthe first stop 80 and the second stop 84 are in contact with each otherand that a sufficient connection has been made. Additionally oralternatively, an optical device 96 may be configured to scan anindicator or marking (e.g., markings 90, 90′, 90″, 92, 92′, 92″) todetermine if a successful connection has been made. For example andwithout limitation, if the indicators or markings are configured aslines (e.g., markings 90, 92), an optical device 96 may be configured todetermine if the lines are aligned, which may indicate that a successfulconnection has been made. If the indicator or markings are configured asa barcode (e.g., markings 90′, 90″, 92′, 92″), an optical device 96 mayscan a fluid fitting 20 and attempt to read the barcode.

With embodiments, if a fluid fitting 20 is not sufficiently connected,the optical device 96 may not be able to read the barcode and/or theoptical device 96 may provide an indication of an insufficientconnection. An indication of an insufficient connection may include, forexample and without limitation, an audible warning and/or a warningmessage that may be displayed on a display 98 of the optical device 96,among other types of indications.

With reference to FIG. 11B, a method 130 of using/operating a fluidfitting 20 with a sliding stop (e.g., with a stop ring 88) may, for someembodiments, include connecting a sleeve 30 with a conduit 32 and/or anut 40 (step 132). The method 130 may include connecting a nut 40 with aunion 60 (step 134). The nut 40 and the union 60 may be screwed together(step 136) until the first stop 80 and the second stop 84 engage eachother (step 138). As generally illustrated in FIG. 5, if the nut 40 andthe union 60 continue to be screwed together after the first stop 80 andthe second stop 84 engage each other (e.g., if nut 40 and/or union 60are over-torqued), a sliding stop may rotate (e.g., the second stop 84and the stop ring 88 may rotate relative to the union 60) (step 140).The force or torque involved in causing the second stop 84 and the stopring 88 to rotate may exceed a threshold value (or an initial thresholdvalue). The threshold value may correspond to a maximum amount of forceexpected to be provided by a user without benefit of a mechanicaladvantage. For example and without limitation, rotating the second stop84 beyond initial contact between the first stop 80 and the second stop84 may involve a wrench or other tool. Once the connecting (e.g.,rotating) of the nut 40 and the union 60 ceases, the second stop 84 may,if over-torqued, be disposed at a different angular position AP₂ thanits initial position AP₁ relative to the union 60. The fluid fitting 20may subsequently be disconnected (step 142). With future or subsequentconnections between the nut 40 and the union 60, the same or a greateramount of rotation, torque, and/or axial force (e.g., over-torqueing)may be used to cause engagement between first stop 80 and second stop 84(step 144). That is, even if the second stop 84 moves from an initialposition AP₁, for example due to an associated deformation fromconnection, with subsequent connections the stop can ensure that theconnection (with the second stop 84 at the subsequent position AP₂) issufficient.

In embodiments, such as generally illustrated in FIGS. 12A and 12B, amethod 170 of designing a fluid fitting 20 may include determining agauge diameter 150 of a component, such as of a nut 40 and/or a union 60(step 172). A center point 152 of the gauge diameter 150 may beidentified or determined (step 174). A plane 154 perpendicular to anaxis 20A of the fluid fitting 20 and that includes the center point 152may be determined (step 176). An intersection point or area 156 wherethreads of the component (e.g., the threads 66 of a union 60) intersectwith the perpendicular plane 154 may be determined (step 178). A stopangle 158 may be determined and/or obtained (step 180). A stop angle 158may correspond to a desired or intended amount of relative rotationbetween two components, such as between a union 60 and a nut 40. A stopposition 160 for a stop of the component (e.g., the second stop 84 ofthe union 60) may be determined according to stop angle 158 and point orarea 156 (step 182). For example and without limitation, a stop position160 may be disposed at the stop angle (e.g., angularly spaced) frompoint or area 156 in a clockwise direction or in a counterclockwisedirection. A fitting 20 (e.g., a stop 84 of a union 60) may be formedaccording to the determined stop position.

In embodiments, a stop angle 158 may be determined according to anexpected plastic deformation, an expected elastic deformation, and/or anexpected amount of axial compression of fitting 20. A stop angle 158 maybe larger if an expected plastic deformation, an expected elasticdeformation, and/or an expected amount of axial compression arerelatively large. A stop angle 158 may be smaller if an expected plasticdeformation, an expected elastic deformation, and/or an expected amountof axial compression are relatively small. A tolerance of a stop angle158 may, for example and without limitation, be about +/−15 degrees toabout +/−30 degrees, and/or about +/−25 degrees (e.g., with respect torelative positions of two stop features).

While a union 60 is shown with outer threads 66, and a nut 40 is shownwith inner threads 48, embodiments of a fitting 20 may include a union60 including inner threads engaging outer threads of a nut 40.

The sleeve 30, the nut 40, and the union 60 are generally described andillustrated as discrete components. However, some or all of suchcomponents (or features thereof) could be associated with componentshaving different names (with similar configurations and/orfunctionality) and/or may be integrated and/or connected with one ormore other/additional components. For example and without limitation, aswould be known to persons of skill in the art, various configurations ofsuch components may comprise a joint, and geometries that are referredto on a sleeve and a union may, for example, be formed (e.g., directlymachined) into complex fittings or other/additional components.

With embodiments, a fluid fitting 20, which may be configured as aflareless fitting, such as a AS18280 style fitting, that may be used inconnection with aircraft. Such fittings 20 may include one or morefeatures that may be desirable and/or better than other designs, suchas, for example and without limitation, improved or superior electricalconductivity, temperature range/compatibility, fluid and environmentalcompatibility, and/or reusability. A sufficient or correct connection ofa flareless fitting may involve an acceptable range of torque, such asaccording to Aerospace Recommended Practice (ARP) 908. Some methods ofevaluating a connection (e.g., via a torque value) may be an indirectmeasurement approach.

In embodiments, such as generally illustrated in FIG. 13, sealing ofcomponents of a fitting 20 (e.g., of a sleeve 30 and a union/adapter 60and/or of a sleeve 30 and a nut 40) may be facilitated and/oraccomplished via a normal stress or sealing pressure between matingadapters (e.g., between a sleeve 30 and a union/adapter 60). A loweracceptable limit for a sealing pressure may be determined or definedaccording to a maximum fluid pressure expected to be contained by thefitting 20. An upper acceptable limit may include a threshold at whichgalling may begin to occur.

In FIG. 13, in connection with contact between a sleeve 30 and a nut 40,P₁ may represent an axial force, σ_(N) may represent a normal traction,τ_(N) may represent friction traction along A_(N), τ_(NC) may representfiction trance along a circumferential direction, A_(N) may represent asleeve-nut contact area, T_(S) may represent sleeve torque, and r_(Nm)may represent mean torque radius at a sleeve-union contact. Thesevalues/variables may be related according to the following equations:τ_(N)=ε_(N)σN  Eq. 1τ_(Nc)=ε_(Nc)σ_(N)  Eq. 20≤(ε² _(N)+ε² _(Nc))^(1/2)≤μ_(N)  Eq. 3P ₁ =A _(N) *B _(N)*σ_(N)*sin(φ_(N)+θ_(N))  Eq. 4tan Φ_(N)=ε_(N)  Eq. 5B _(N)=(1+ε_(N) ²)^(1/2)  Eq. 6T _(S)=τ_(c) *A*r _(Nm)  Eq. 7σ_(N) =P ₁/(A _(N)*sin θ_(N))  Eq. 8τ_(Nc)=μ_(N) *P ₁/(A _(N)*sin θ_(N))  Eq. 9T _(S)=μ_(N) *r _(Nm) *P ₁/sin θ_(N)  Eq. 10τ_(c)=(μ_(N)/sin θ_(N))(r _(Nm) /r _(m))P ₁ /A  Eq. 11τ_(c)=ε_(c)σ  Eq. 12ε_(c)=(μ_(N)/sin θ_(N))(r _(Nm) /r _(m))(1+ε²)^(1/2) sin(φ+θ)  Eq. 13

The following assumptions may be applied:ε_(N)=0  Eq. 14ε_(Nc)=μ_(N)  Eq. 15φ_(N)=0  Eq. 16B _(N)=1  Eq. 17

In connection with contact between a sleeve 30 and a union 60, σ mayrepresent normal traction (e.g., sealing pressure), τ may representfriction traction along A, τ_(C) may represent friction traction along acircumferential direction, A may represent sleeve-union contact area,A_(r) may represent a radial projection of A, A_(a) may represent anaxial projection of A, k_(r) may represent a radial stiffness, u_(r) mayrepresent radial displacement, u_(a) may represent axial displacement, αmay represent nut angular rotation (e.g., in radians), l_(t) mayrepresent a nut thread lead, T_(s) may represent a sleeve torque, r_(m)may represent a mean torque radius at sleeve-union contact, σ_(r) mayrepresent radial stress, and σ_(a) may represent axial stress. Thesevalues/variables may be related according to the following equations:τ=εσ  Eq. 18τ_(c)=ε_(c)σ  Eq. 190≤(ε²+ε² _(c))^(1/2)≤μ  Eq. 20P ₂ =A*B*σ*sin(φ+θ)  Eq. 21tan Φ=ε  Eq. 22B=(1+ε²)^(1/2)  Eq. 23σ_(r) =P ₂*sin(ψ−θ)/(A*cos θ*sin(φ+θ))  Eq. 24σ_(a) =P ₂/(A*sin θ)  Eq. 25tan ψ=1/ε  Eq. 26σ_(r) =k _(r) *u _(r) /A _(r)  Eq. 27u _(r) =u _(a)*tan θ  Eq. 28u _(a) =l _(t)*α/(2π)  Eq. 29T _(S)=τ_(c) *A*r _(m)  Eq. 30ε²+ε²=μ²  Eq. 31μ²−ε²=(μ_(N)/sin θ_(N))(r _(Nm) /r _(m))(1+ε²)^(1/2) sin(φ+θ)  Eq. 32

Equations 13 and 32 may be solved for ε. A radial stress σ_(r), normaltraction σ (sealing pressure), and/or an axial force P₁, P₂, may bedetermined for a given nut rotation and radial stiffness. Inembodiments, P₁ may equal P₂. Equations 18 and 19 may be solved forfriction tractions at a sleeve-union interface. Equation 7 and/orEquation 30 may be solved for a sleeve torque T_(s). A nut torque T_(t)due to threads may be determined, such as according to nut factorcalculations. A total torque T may be represented as:T=T _(S) +T _(t)  Eq. 33

A nut axial force Pt may be represented as:P _(t) =K*T _(t) *d  Eq. 34

T_(t) may represent a nut torque, K may represent a nut factor, and/or dmay represent a nut average diameter. Nut factor K may include one ormore effects of nut geometry as well as friction. During tightening,P_(t) may equal P₁ or P₂ (which may be equal). During pressurization,P_(t) may be different than P₁ or P₂.

One more assumptions may apply. For example and without limitation, itmay be assumed that contact always occurs at constant angle and constantarea, all tractions and stresses in sleeve nose are constant over area,interior shear stresses are negligible, radial stiffness is independentof angle, radial stiffness is uncoupled from other stiffness, uniondeformation is negligible (so radial displacement may be dictated bygeometry u_(r)=u_(a)*tan(θ)), axial deformation of the sleeve 30 isnegligible (so the sleeve 30 travels with the nut 40 like a rigid bodyu_(a)=(l_(t)/2*π)*α), a slip condition is present at the sleeve-nutbearing contact, frictional forces act only in the circumferentialdirection (which may be verified by finite element analysis or FEA),and/o a slip condition is present at the sleeve-union interface.

With some torque-based connection methods, a torque value may be relatedto an acceptable sealing pressure. In embodiments of methods of thepresent disclosure, a sealing pressure may be predicted. A relationshipincluding all of the geometry of the mating components may be relativelycomplicated (e.g., as described above), but may be simplified toEquation 34. Axial force P_(t) may be related to sealing pressure, suchas via a geometrical relationship. A relatively small variation infriction can have a relatively significant effect on sealing pressure.For example and without limitation, a stainless steel −4 fitting may betorqued to a minimum ARP 908 value of 135 in-lbs (15.25 Nm) with minimallubrication and may have as low as 34,224 psi (236 MPa) of sealingpressure at the location of the gage point. Additionally oralternatively, that same connection with ideal lubrication may betorqued to a maximum allowable torque of 190 in-lbs (21.47 Nm) and mayhave as much as 175,547 psi (1210 MPa) of sealing pressure at the gagepoint, which may correspond to variation in excess of 100 ksi betweenconnections.

With embodiments of the present disclosure, a desired sealing pressuremay be maintained via control of a position of a nut 40 (e.g., ratherthan via torque values). Controlling a position of a nut 40 may includedetermining an appropriate lower specification limit (LSL), determiningan appropriate upper specification limit (USL), determiningmanufacturing capabilities (e.g., associated with nut positionplacement), and/or determining inspection capabilities (e.g., associatedwith nut position placement).

In embodiments, an LSL may be determined according to one or morefactors, such as component tolerances, temperature variation, repeatedconnections, and/or vibration. Increases in these factors may negativelyimpact sealing pressure. A minimum allowable sealing pressure (e.g., atheoretical minimum) may be determined as an LSL for nut position as oneor more of these factors are evaluated and/or quantified.

In embodiments, a USL for nut position may be determined such that atorque involved to achieve a desired position may not exceed that of atypical or expected connection. A USL may be sufficiently low thatgalling may not occur and/or may be relatively insignificant.

With embodiments, fittings 20 may be designed to be compatible withconditions more severe than expected conditions, such as four times moresevere than design operating pressure conditions.

In embodiments, a method of manufacturing and inspecting/verifying afitting 20 may include directly dimensioning an axial position or angleof a gage point relative to thread position. The axial position of thegage point may be inspected, such as, for example and withoutlimitation, via CMM (coordinate measuring machine) touch-probetechnology and/or a CMM touch-probe machine. Embodiments of methods mayinclude tightening tolerances.

Some methods of dimensioning/tolerancing may not be configured toestablish proper nut positioning. For example and without limitation,with some methods, tolerance stack-ups may result in a variation of nutposition in excess of one complete rotation.

In embodiments, angular stop position on a nut 40 and/or a union 60, incombination with a length of a sleeve 30, may control and/or dictatevariation in nut position. As each component of a fitting 20 isdesigned, manufacturing and/or inspection capabilities may be evaluated(e.g., for compatibility with nut-position control methods). Ifmanufacturing is not adequate for determined performance limits, one ormore geometry changes may be made to the fitting 20 to influence thechange of sealing pressure of the fitting 20 per turn of the nut 40.Geometry changes may include, for example and without limitation, (i)changes to a radius of a sealing surface, which may change a footprintat a gage point (a relatively small change in radius may provide arelatively large change in the sealing surface), (ii) changes to threadpitch, and/or (iii) changes to the inner diameter and/or outer diameterof fitting components, which may change the stiffness of the fitting 20(e.g., effectively a spring rate of the fitting system).

FIG. 14 is graphical representation of sealing pressure relative todegrees from finger-tight position.

FIG. 15 is a perspective view generally illustrating an embodiment of anadapter or union 60.

With embodiments, such as generally illustrated in FIG. 16, a method 200of designing, manufacturing, and/or verifying a fitting 20 may includedetermining desired sealing pressure and/or limits for nut position(step 202). Safety margins may be added to compensate for factors suchas repeated use and vibration (step 204). Whether manufacturingtechnology is compatible with the designed fitting may be determined(step 206). If manufacturing is not adequate for determined performancelimits, one or more geometry changes may be made to the fitting 20 (step208). If manufacturing technology is compatible, the fitting 20 may bemanufactured (step 210), such as without adjusting other features of thefitting 20. Verification testing may be performed (step 212), which mayaddress one or more specifications, such as the AS18280 specificationand/or the RTCA (Radio Technical Commission for Aeronautics) DO-160specification. Verification testing may include one or more of repeatedassembly (e.g., increased cycle count and increased pressureevaluation), flexure, impulse, burst, vibration, lighting, sand/dust,and/or icing testing. Testing may continue until failure, such as todetermine statistical robustness.

In embodiments, one or more components of a fitting 20 may bemanufactured or formed with advanced machining methods and/or threadtiming. With embodiments, a total tolerance stack of a fitting 20 may beabout +/−0.003 inches, compared with other fittings that may include atotal tolerance stack of about +/−0.038 inches. It may be desirable forrelative axial travel to exceed a tolerance stack. Relative axialmovement of components of a fitting 20 may exceed 0.003 inches. One ormore wear resistant coatings may be applied to one or more components ofa fitting 20, such as to limit or prevent galling.

With embodiments, one or more components of a fitting 20, such as asleeve 30, a nut 40, and/or a union 60 may, for example and withoutlimitation, be metal. Connecting a sleeve 30 with a union 60 may includeforming a metal-to-metal fluid seal between the sleeve 30 and the union60.

Various embodiments are described herein for various apparatuses,systems, and/or methods. Numerous specific details are set forth toprovide a thorough understanding of the overall structure, function,manufacture, and use of the embodiments as described in thespecification and illustrated in the accompanying drawings. It will beunderstood by those skilled in the art, however, that the embodimentsmay be practiced without such specific details. In other instances,well-known operations, components, and elements have not been describedin detail so as not to obscure the embodiments described in thespecification. Those of ordinary skill in the art will understand thatthe embodiments described and illustrated herein are non-limitingexamples, and thus it can be appreciated that the specific structuraland functional details disclosed herein may be representative and do notnecessarily limit the scope of the embodiments.

Reference throughout the specification to “various embodiments,” “withembodiments,” “in embodiments,” or “an embodiment,” or the like, meansthat a particular feature, structure, or characteristic described inconnection with the embodiment is included in at least one embodiment.Thus, appearances of the phrases “in various embodiments,” “withembodiments,” “in embodiments,” or “an embodiment,” or the like, inplaces throughout the specification are not necessarily all referring tothe same embodiment. Furthermore, the particular features, structures,or characteristics may be combined in any suitable manner in one or moreembodiments. Thus, the particular features, structures, orcharacteristics illustrated or described in connection with oneembodiment/example may be combined, in whole or in part, with thefeatures, structures, functions, and/or characteristics of one or moreother embodiments/examples without limitation given that suchcombination is not illogical or non-functional. Moreover, manymodifications may be made to adapt a particular situation or material tothe teachings of the present disclosure without departing from the scopethereof.

It should be understood that references to a single element are notnecessarily so limited and may include one or more of such element. Anydirectional references (e.g., plus, minus, upper, lower, upward,downward, left, right, leftward, rightward, top, bottom, above, below,vertical, horizontal, clockwise, and counterclockwise) are only used foridentification purposes to aid the reader's understanding of the presentdisclosure, and do not create limitations, particularly as to theposition, orientation, or use of embodiments.

Joinder references (e.g., attached, coupled, connected, and the like)are to be construed broadly and may include intermediate members betweena connection of elements and relative movement between elements. Assuch, joinder references do not necessarily imply that two elements aredirectly connected/coupled and in fixed relation to each other. The useof “e.g.” in the specification is to be construed broadly and is used toprovide non-limiting examples of embodiments of the disclosure, and thedisclosure is not limited to such examples. Uses of “and” and “or” areto be construed broadly (e.g., to be treated as “and/or”). For exampleand without limitation, uses of “and” do not necessarily require allelements or features listed, and uses of “or” are intended to beinclusive unless such a construction would be illogical.

It is intended that all matter contained in the above description orshown in the accompanying drawings shall be interpreted as illustrativeonly and not limiting. Changes in detail or structure may be madewithout departing from the present disclosure.

What is claimed is:
 1. A fluid fitting, comprising: a nut including aninner surface or flange; a sleeve including a flange; and a union havingthreads and a stop, the union including: a gauge diameter having acenter point and an axis of rotation, the axis of rotation defining aplane perpendicular to the union and including the center point of thegauge diameter; and a point of intersection defined by the threads ofthe union and the plane perpendicular to the union, a position of thestop is determined according to an angle from the point of intersection;wherein the nut includes a stop corresponding to the stop of the union,the corresponding stops contact or engage with each other when a limitof a degree to which the nut is able to be screwed onto the union isreached, and the inner surface or flange of the nut engages the flangeof the sleeve such that axial movement of the nut in at least onedirection causes axial movement of the sleeve.
 2. The fluid fitting ofclaim 1, wherein corresponding mating surfaces of the sleeve and theunion include a mating angle of about 10 degrees to about 14 degrees. 3.The fluid fitting of claim 1, wherein corresponding mating surfaces ofthe sleeve and the union include a mating angle of about 4 degrees toabout 6 degrees.
 4. The fluid fitting of claim 1, wherein thecorresponding stops are helical and include correspondingcircumferential faces.
 5. The fluid fitting of claim 1, wherein thecorresponding stops include corresponding fingers that form a unitarystructure with a body of the respective union and nut.
 6. The fluidfitting of claim 1, wherein the stop of the union includes a stop ringconnected with the union via a press fit or interference fit.
 7. Thefluid fitting of claim 1, wherein the corresponding stops include atleast two stops of the nut and at least two stops of the union.
 8. Thefluid fitting of claim 1, wherein the union and the nut includecorresponding visual indicators.
 9. The fluid fitting of claim 8,wherein the corresponding visual indicators include a first visualindicator of the union and a second visual indicator of the nut.
 10. Thefluid fitting of claim 9, wherein one of the first visual indicator andthe second visual indicator has a greater circumferential extent thanthe other.
 11. The fluid fitting of claim 8, wherein, in a connectedconfiguration of the union and the nut, the corresponding visualindicators are readable via an electronic scanner.
 12. The fluid fittingof claim 1, wherein the stop of the nut is a sliding stop configured torotate relative to the nut, and the stop of the union is a sliding stopconfigured to rotate relative to the union.
 13. The fluid fitting ofclaim 1, wherein the angle is associated with or corresponds to anexpected deformation.
 14. The fluid fitting of claim 13, wherein theexpected deformation includes an expected plastic deformation and anexpected elastic deformation.
 15. The fluid fitting of claim 13, whereina range of expected deformation is determined according to a minimumlimit and a maximum limit.
 16. The fluid fitting of claim 15, whereinthe minimum limit is determined based upon an expected sealing pressureloss during an expected life of the fluid fitting as a result of one ormore of repeated use, vibration, component tolerances, or temperaturevariation.
 17. The fluid fitting of claim 15, wherein the maximum limitis determined based upon at least one of a maximum torque and a torqueat which galling occurs.
 18. The fluid fitting of claim 1, wherein theangle is determined via coordinate measuring machine (CMM) touch-probetechnology.
 19. A method of designing a fluid fitting according to claim1 comprising: determining the gauge diameter of the union; determiningthe plane perpendicular to the axis of rotation of the union thatincludes the center point of the gauge diameter; determining the pointof intersection of threads of the union with the perpendicular plane;and determining the position of the stop according to the angle from thepoint of intersection.
 20. A method of connecting a fitting, the methodcomprising: providing a fitting in accordance with claim 1; connectingthe sleeve of the fitting with the nut of the fitting, the inner surfaceor flange engaging the flange of the sleeve such that axial movement ofthe nut causes axial movement of the sleeve; connecting the nut with theunion; rotating at least one of the nut and the union until a stop ofthe nut engages a stop of the union when the limit of a degree to whichthe nut is able to be screwed onto the union is reached; restrictingover torque via the stop of the nut and the stop of the union; andverifying a sufficient connection of the nut and the union.